PEC-PRO: A new prognostic score from a series of 87 patients with localized perivascular epithelioid cell neoplasms (PEComas) treated with curative intent.

BACKGROUND: Perivascular epithelioid cell neoplasms (PEComas) encompass a heterogeneous family of mesenchymal tumors. Previously described clinicopathologic features aimed at distinguishing benign from malignant variants but lacked prognostic value. METHODS: This retrospective analysis examined clinicopathologic data from patients who had localized PEComa across French Sarcoma Network centers. The authors analyzed 12 clinicopathologic features in a Cox proportional hazard framework to derive a multivariate prognostic risk model for event-free survival (EFS). They built the PEComa prognostic score (PEC-PRO), in which scores ranged from 0 to 5, based on the coefficients of the multivariate model. Three groups were identified: low risk (score = 0), intermediate risk (score = 1), and high risk (score ≥ 2). RESULTS: Analyzing 87 patients who had a median 46-month follow-up (interquartile range, 20-74 months), the median EFS was 96.5 months (95% confidence interval [CI], 47.1 months to not applicable), with 2-year and 5-year EFS rates of 64.7% and 58%, respectively. The median overall survival was unreached, with 2-year and 5-year overall survival rates of 82.3% and 69.3%, respectively. The simplified Folpe classification did not correlate with EFS. Multivariate analysis identified three factors affecting EFS: positive surgical margins (hazard ratio [HR], 5.17; 95% CI, 1.65-16.24; p = .008), necrosis (HR, 3.94; 95% CI, 1.16-13.43; p = .030), and male sex (HR, 3.13; 95% CI, 1.19-8.27; p = 0.023). Four variables were retained in the prognostic model. Patients with low-risk PEC-PRO scores had a 2-year EFS rate of 93.7% (95% CI, 83.8%-100.0%), those with intermediate-risk PEC-PRO scores had a 2-year EFS rate of 67.4% (95% CI, 53.9%-80.9%), and those with high-risk PEC-PRO scores had a 2-year EFS rate of 2.3% (95% CI, 0.0%-18.3%). CONCLUSIONS: The PEC-PRO score reliably predicts the risk of postoperative recurrence in patients with localized PEComa. It has the potential to improve follow-up strategies but requires validation in a prospective trial.

Glycoprotein Nonmetastatic Melanoma Protein B (GPNMB) Immunohistochemistry Can Be a Useful Ancillary Tool to Identify Perivascular Epithelioid Cell Tumor.

Perivascular epithelioid cell tumors (PEComas) are rare mesenchymal tumors that express smooth muscle and melanocytic makers. Diagnosis of PEComas can be challenging due to focal or lost expression of traditional immunohistochemical markers, limited availability of molecular testing, and morphological overlap with much more common smooth muscle tumors. This study evaluates the use of glycoprotein nonmetastatic melanoma protein B (GPNMB) immunohistochemical staining as a surrogate marker for TSC1/2/MTOR alteration or TFE3 rearrangement to differentiate PEComas from other mesenchymal tumors. Cathepsin K was also assessed for comparison. A total of 399 tumors, including PEComas, alveolar soft part sarcomas, and other histologic PEComa mimics, were analyzed using GPNMB and cathepsin K immunohistochemistry. GPNMB expression was seen in all PEComas and alveolar soft part sarcomas with the majority showing diffuse and moderate-to-strong labeling, whereas other sarcomas were negative or showed focal labeling. When a cutoff of diffuse and at least moderate staining was used, GPNMB demonstrated 95% sensitivity and 97% specificity in distinguishing PEComas from leiomyosarcoma, well-differentiated/dedifferentiated liposarcomas, and undifferentiated pleomorphic sarcomas. Cathepsin K with a cutoff of any labeling had lower sensitivity (78%) and similar specificity (94%) to GPNMB. This study highlights GPNMB as a highly sensitive marker for PEComas and suggests its potential use as an ancillary tool within a panel of markers for accurate classification of these tumors.

Sarcomas With RAD51B Fusions Are Associated With a Heterogeneous Phenotype.

RAD51B-rearranged sarcomas are rare neoplasms that exhibit a heterogeneous morphology. To date, 6 cases have been reported, all involving the uterus, including 4 perivascular epithelioid cell tumors (PEComas) and 2 leiomyosarcomas (LMS). In this study, we describe the morphologic, immunohistochemical, and molecular features of 8 additional sarcomas with RAD51B rearrangement, including the first extrauterine example. All patients were women with a median age of 57 years at presentation. Seven tumors originated in the uterus, and one in the lower extremity soft tissue, with a median tumor size of 12 cm. Histologically, 4 tumors showed predominantly spindle cell morphology with eosinophilic fibrillary cytoplasm, with or without nuclear pleomorphism, whereas 2 tumors exhibited pleomorphic epithelioid cells, featuring clear to eosinophilic, granular cytoplasm. Two neoplasms exhibited undifferentiated cytomorphology, including one with uniform small blue round cells. All tumors showed high-grade cytologic atypia and high mitotic activity (median: 30/10 high-power fields), whereas coagulative necrosis was noted in 6 cases and lymphovascular invasion in 2. By immunohistochemistry, 2 showed myoid and melanocytic markers in keeping with PEComa, whereas 4 cases were only positive for smooth muscle markers consistent with LMS (including 3 myxoid). The remaining 2 cases had a nonspecific immunoprofile. Five cases tested by targeted RNA sequencing (Archer FusionPlex, Illumina TruSight) showed different fusion partners (HMGA2, PDDC1, and CEP170). RAD51B rearrangements were identified by FISH in the remaining 3 cases. Targeted DNA sequencing in 2 cases was negative for TSC gene alterations. Clinical outcome, available in 5 patients (median follow-up, 19 months), revealed 3 local recurrences, 2 lung metastases, and 4 deaths due to disease. Our results expand the spectrum of sarcomas with RAD51B fusions, demonstrating variable clinical presentations, morphologic spectrum, and fusion partners. These tumors have a predilection for a uterine location, with either LMS, PEComa, or undifferentiated phenotypes, and are associated with an aggressive clinical course.

PEComa with ASPSCR1::TFE3 fusion: expanding the molecular genetic spectrum of TFE3-rearranged PEComa with an emphasis on overlap with alveolar soft part sarcoma.

AIMS: Mesenchymal neoplasms involving TFE3 gene fusions are diverse, mainly include alveolar soft part sarcoma (ASPS) that is characterised by ASPSCR1::TFE3 fusion, and a small subset of perivascular epithelioid cell tumours (PEComas) referred to as TFE3-rearranged PEComa, that most frequently harbours SFPQ::TFE3 fusion. Historically, ASPS and TFE3-rearranged PEComa are considered two distinctive entities despite their known morphological overlap. However, recent studies have suggested a potential histogenetic relationship between them, and several neoplasms that showed morphological features more closely fit PEComa rather than ASPS but harboured ASPSCR1::TFE3 fusion have been documented. In this study, we report three cases of PEComa with ASPSCR1::TFE3 fusion. METHODS AND RESULTS: Clinicopathological features were assessed and partner agnostic targeted next-generation sequencing on clinically validated platforms were performed. The patients are two females and one male with age at presentation ranging from 21 to 51 years. All three tumours were located in the viscera (rectum, kidney and cervix). On a relatively limited follow-up period (range = 9-15 months), all patients are alive without evidence of recurrent or metastatic disease. The neoplasms were composed of tight nested architecture of epithelioid clear cells separated by a delicate vascular network, two of which were associated with sheets of plump spindle cells, and none showed significant discohesive tumour morphology. Immunohistochemically, in addition to TFE3 protein, all three neoplasms demonstrated co-expression of melan-A and smooth muscle actin. RNA-sequencing identified ASPSCR1::TFE3 fusion in all three cases that were confirmed by subsequent fluorescence in-situ hybridisation analyses. CONCLUSIONS: Our study expands the molecular genetic spectrum of TFE3-rearranged PEComa and further indicates its close relationship to ASPS.

Systematic analysis of perivascular epithelioid cell neoplasms in the female reproductive tract: a comprehensive review.

Perivascular epithelioid cell neoplasms (PEComas) are rare mesenchymal lesions, with gynecological PEComas accounting for just over a quarter of cases. Limited reports exist on gynecological PEComa, primarily treated with surgery; adjuvant therapy is considered in high-risk cases. This systematic review aims to summarize the origin and clinical, pathological and molecular characteristics of uterine PEComa, focusing on treatment options for gynecological PEComa. A comprehensive PubMed review of gynecological PEComa reports was conducted. A detailed examination of the literature ensured a thorough understanding. Gynecological PEComa diagnosis relies on histology and immunology. Despite therapy controversies, surgery remains the mainstay. Adjuvant therapy efficacy in high-risk cases is uncertain. mTOR inhibitors are the first line; alternative treatments, including angiogenesis and aromatase inhibitors, should be considered.

A retrospective clinical analysis of 11 cases of PEComa from different sites.

PURPOSE: The objective of this paper is to offer a thorough examination of the clinical presentations, etiology, and treatment strategies associated with perivascular epithelioid cell tumors (PEComas). METHODS: This retrospective study examined the comprehensive archival data of PEComa cases diagnosed at Beijing Hospital from 2015 to 2023. The pathology slides of all patients were thoroughly reassessed by two experienced pathologists. A thorough retrospective analysis was undertaken, incorporating clinicopathological data including gender, age at diagnosis, initial clinical manifestations, signs, disease onset site, tumor markers, imaging findings, therapeutic modalities, pathological features, immunohistochemical profiles, treatment responses, and prognostic indicators. Patients were evaluated for disease severity according to established pathological classification criteria and were followed up until the designated analysis cut-off date. In instances where patients were unable to be monitored on-site, they were contacted via telephone for postoperative follow-up inquiries. RESULTS: This study included 11 patients with ages ranging from 17 to 66 years old, presenting with the disease in multiple anatomical sites, including the retroperitoneum (2/11), liver (4/11), kidney (4/11), lung (1/11), and broad ligament of the uterus (1/11). Most patients presented with non-specific clinical symptoms and were subsequently diagnosed with space-occupying lesions upon physical examination. The tumor demonstrated progressive growth and enlargement, which could result in compression of neighboring organs. Preoperative imaging alone is insufficient for a definitive diagnosis of PEComa, but MRI can provide an initial evaluation of the tumor's potential malignancy. Molecular marker testing specific to PEComa, such as HMB-45 (90.0%), SMA (81.8%), Melan-A (90.9%), vimentin (90.9%), and Desmin (36.3%), was conducted on all patients. No adjuvant therapies were administered postoperatively. Upon analysis, no instances of relapse at the primary site or the development of new tumors at other sites were observed. Regular imaging reviews of three patients with malignant PEComa post-surgery showed no evidence of recurrence. CONCLUSIONS: The clinical presentation, tumor biomarkers, and imaging characteristics of PEComa lack specificity, necessitating dependence on pathology and immunohistochemistry for precise diagnosis. The mainstay of treatment consists of surgical resection, with patients typically experiencing a favorable prognosis.

Gynecologic perivascular epithelioid cell tumors (PEComas): a review of recent evidence.

Gynecologic perivascular epithelioid cell (PEC) tumors, or 'PEComas,' represent a rare and intriguing subset of tumors within the female reproductive tract. This systematic literature review aims to provide an updated understanding of gynecologic PEComas based on available literature and data. Although PEComa is rare, there are varied tumor-site presentations across gynecologic organs, with uterine PEComas being the most prevalent. There is scarce high-quality literature regarding gynecologic PEComa, and studies on malignant PEComa underscore the challenges in diagnosis. Among the diverse mutations, mTOR alterations are the most prominent. Survival analysis reveals a high rate of local recurrence and metastatic disease, which commonly affects the lungs. Treatment strategies are limited, however mTOR inhibitors have pivotal role when indicated and chemotherapy may also be used. with some cases demonstrating promising responses. The paucity of data underscores the need for multicentric studies, an international registry for PEComas, and standardized reporting in case series to enhance clinical and pathological data.

Pancreatic PEComa, a not so uncommon neoplasm? Systematic review and therapeutic update. / PEComa pancreático ¿una neoplasia no tan infrecuente? Revisión sistemática y actualización clínico-terapéutica.

Pancreatic PEComas are extremely rare neoplasms with malignant potential, which mostly affect middle-aged women and are characterized by presenting melanocytic and myogenic markers in immunohistochemical analysis. There are no symptoms or pathognomonic imaging tests, so the diagnosis is established with the analysis of the surgical specimen or the FNA obtained with preoperative endoscopic ultrasound. The mean treatment consists on radical excision, adapting the intervention to the location of the tumor. To date, 34 cases have been described; however, more than 80% of them have been reported in the last decade, which suggests that it is a more frequent pathology than expected. A new case of pancreatic PEComa is reported and a systematic review of the literature is carried out according to the PRISMA guidelines with the aim of divulge this pathology, deepening its knowledge and updating its management.

Primary Liver Perivascular Epithelioid Cell Tumor (PEComa): Case Report and Literature Review.

A primary liver perivascular epithelioid cell tumor (PEComa) is an extremely rare entity. In this article, we present a case report with a review of the literature on the patients diagnosed with primary liver PEComa and an elaboration of diagnostic and treatment modalities. A systematic literature search was conducted using the terms "perivascular epithelioid cell tumor", "PEComa", "liver", and "hepatic". All articles describing patients diagnosed with primary liver PEComa were included. We identified a total of 224 patients of primary liver PEComa from 75 articles and a case from the present study with a significant preponderance of females (ratio 4:1) and with a mean age of 45.3 ± 12.1 years. Most of the patients (114 out of 224, 50.9%) were asymptomatic. A total of 183 (81.3%) patients underwent surgical hepatic resection at the time of diagnosis, while 19 (8.4%) underwent surveillance. Recurrence and metastases were detected in seven (3.1%) and six (2.7%) patients, respectively. In conclusion, surgical resection remains the cornerstone of therapy; however, the presence of nonspecific imaging features makes it difficult to reach a definite diagnosis preoperatively. Therefore, a multidisciplinary approach should be the gold standard in selecting the treatment modality.

[TFE3-rearranged perivascular epithelioid cell tumors: a clinicopathological analysis of eight cases].

Objective: To investigate the clinicopathological, immunohistochemical and molecular genetic characteristics of TFE3-rearranged perivascular epithelioid cell tumor (PEComa). Methods: Eight cases of PEComa with TFE3 rearrangement diagnosed in the First Affiliated Hospital of Air Force Medical University from January 2014 to July 2022 were collected. Three were consultation cases and 5 were collected from our hospital; 7 cases were resection specimens and 1 case was a needle biopsy specimen. Routine histolopathological analysis, immunohistochemical staining, fluorescence in situ hybridization (FISH) and the next-generation sequencing were performed. Clinical data were collected and the prognosis was assessed. Results: The 8 patients consisted of 5 females and 3 males with a median age of 45 years (ranged from 25 to 65 years). The tumor location included 1 uterus, 1 liver, 1 urachus, 2 kidneys, 1 abdominal cavity, 1 colon, and 1 retroperitoneum (3 subsequent recurrences in the abdominal cavity, pelvis and ovary, and abdominal cavity, respectively). Morphologically, the tumor cells were uniform and epithelioid with translucent or eosinophilic cytoplasm. They were arranged in nests or sheets, most of which were separated by thin-walled blood vessels. There were no papillary structures, and no overt smooth muscle or fat components. Atypical features were seen in 3 cases, with bizarre nuclei and tumor giant cells. Large areas of necrosis were visible, and mitosis was common (up to 28/50 HPF). Melanin deposition was present in 3 cases. Immunohistochemical staining showed diffuse and strong positivity for TFE3 in 8/8 cases and for HMB45 in 6/8 cases; focal positivity for Cathepsin K and Melan-A in 6/8 cases and for SMA in 2/8 of cases. All cases were negative for CKpan, PAX8 and Desmin. TFE3 gene break-apart was detected by FISH in all 8 cases, 4 of which underwent next-generation sequencing, and it revealed that 2 cases presented with SFPQ::TFE3 fusion, 1 case with ASPSCR1::TFE3 fusion, and 1 case with no chimeric fusion. Seven cases were followed up for 4-94 months. All cases were alive; 4 cases were disease-free, 2 cases showed recurrence, and 1 case had metastasis at initial diagnosis. Conclusions: TFE3-rearranged PEComa has unique histomorphological, immunohistochemical and molecular characteristics. The biological behavior is aggressive, which could lead to recurrence and metastasis, and warrants close clinical follow-up.

GPNMB expression identifies TSC1/2/mTOR-associated and MiT family translocation-driven renal neoplasms.

GPNMB (glycoprotein nonmetastatic B) and other TFE3/TFEB transcriptional targets have been proposed as markers for microphthalmia (MiT) translocation renal cell carcinomas (tRCCs). We recently demonstrated that constitutive mTORC1 activation via TSC1/2 loss leads to increased activity of TFE3/TFEB, suggesting that the pathogenesis and molecular markers for tRCCs and TSC1/2-associated tumors may be overlapping. We examined GPNMB expression in human kidney and angiomyolipoma (AML) cell lines with TSC2 and/or TFE3/TFEB loss produced using CRISPR-Cas9 genome editing as well as in a mouse model of Tsc2 inactivation-driven renal tumorigenesis. Using an automated immunohistochemistry (IHC) assay for GPNMB, digital image analysis was employed to quantitatively score expression in clear cell RCC (ccRCC, n = 87), papillary RCC (papRCC, n = 53), chromophobe RCC (chRCC, n = 34), oncocytoma (n = 4), TFE3- or TFEB-driven tRCC (n = 56), eosinophilic solid and cystic RCC (ESC, n = 6), eosinophilic vacuolated tumor (EVT, n = 4), and low-grade oncocytic tumor (LOT, n = 3), as well as AML (n = 29) and perivascular epithelioid cell tumors (PEComas, n = 8). In cell lines, GPNMB was upregulated following TSC2 loss in a MiT/TFE- and mTORC1-dependent fashion. Renal tumors in Tsc2+/- A/J mice showed upregulation of GPNMB compared with normal kidney. Mean GPNMB expression was significantly higher in tRCC than in ccRCC (p < 0.0001), papRCC (p < 0.0001), and chRCC (p < 0.0001). GPNMB expression in TSC1/2/MTOR alteration-associated renal tumors (including ESC, LOT, AML, and PEComa) was comparable to that in tRCC. The immunophenotype of tRCC and TSC1/2/MTOR alteration-associated renal tumors is highly overlapping, likely due to the increased activity of TFE3/TFEB in both, revealing an important caveat regarding the use of TFE3/TFEB-transcriptional targets as diagnostic markers. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

A rare case of primary cutaneous malignant perivascular epithelioid cell tumor and review of the literature.

A 77-year-old female presented with a 6-month history of a 2-cm pink exophytic tumor on the right anterior shin, which had grown rapidly and began to bleed over the last 4 weeks. A shave biopsy showed a dermal proliferation of epithelioid spindled cells, arranged in nests and trabeculae associated with thin-walled capillary vessels. The cells showed pleomorphic nuclei with vacuolated nuclear chromatin and occasional prominent nucleoli. Mitotic figures (7/10 high-power fields [HPFs]), including atypical forms, were present in the specimen. Immunohistochemical staining was negative for SOX10 and stained positive for MiTF. The histopathologic findings were consistent with a malignant perivascular epithelioid cell tumor (PEComa). A malignant PEComa is a rare entity of mesenchymal-derived cells with both melanocytic and myocytic differentiation. A PEComa is considered to be malignant by fulfilling two of the following criteria: size greater than 5 cm, vascular invasion, necrosis, mitotic figures greater than 1 per 50 HPF, infiltrative growth pattern, high nuclear grade, and hypercellularity. PEComas show immunohistochemical positivity to myocytic markers such as SMA, pan-muscle actin, muscle myosin, calponin, and h-caldesmon as well as melanocytic markers such as HMB-45, Melan-A, tyrosinase, and MiTF.

NONO::TFE3 fusion cutaneous epithelioid and spindle cell tumor: A case series.

The NONO::TFE3 fusion has been described in MiT family translocation renal cell carcinomas as well as extracutaneous perivascular epithelioid cell tumors (PEComas). PEComas are known to express myogenic and melanocytic markers but SOX10 and p63 positivity has never been reported. We report two primary cutaneous tumors that morphologically and molecularly fit PEComas, both harboring the NONO::TFE3 fusion, but with an unusual immunophenotype of SOX10 and p63 positivity. One case was on an 80-year-old male's finger, and the other one was on a 72-year-old female's thigh. Both were well-circumscribed multinodular dermal tumors composed of nests of monotonous epithelioid to spindled cells with pale to vacuolated cytoplasm, some of which were arranged around blood vessels. Both tumors were positive for SOX10, S100, and p63, focally positive for Melan-A, and negative for myogenic markers. There are very little data regarding the molecular findings of primary cutaneous PEComas. While the NONO::TFE3 fusion has been identified in extracutaneous PEComas, it has never been reported in primary cutaneous cases. We believe these cases represent a previously undescribed subtype of cutaneous tumor which shows some immunophenotypic expression of melanocytic markers and we named these cases NONO::TFE3 fusion cutaneous epithelioid and spindle cell tumor. Further, we raise the question of whether this tumor should fall under the rubric of PEComa because of its morphology, partial expression of melanocytic markers, and the presence of the NONO::TFE3 fusion, or whether these tumors represent a separate novel class of tumors since the immunophenotypic expression of SOX10 and p63 is unusual for PEComas.

Surprising genetic and pathological findings in a patient with giant bilateral periadrenal tumours: PEComas and mutations of PTCH1 in Gorlin-Goltz syndrome.

Gorlin-Goltz syndrome (GGS) or nevoid basal cell carcinoma syndrome is a rare tumour-overgrowth syndrome associated with multiple developmental anomalies and a wide variety of tumours. Here, we describe a case of a man aged 23 years with GGS with bilateral giant tumours adjacent to both adrenals that raised the suspicion of malignancy on imaging. Histological analysis of both surgically resected tumours revealed perivascular epitheloid cell tumours (PEComas) that were independent of the adrenals. Exome sequencing of the patient's blood sample revealed a novel germline heterozygous frameshift mutation in the PTCH1 gene. As a second hit, a somatic five nucleotide long deletion in the PTCH1 gene was demonstrated in the tumour DNA of both PEComas. To the best of our knowledge, this is the first report on PEComa in GGS, and this finding also raises the potential relevance of PTCH1 mutations and altered sonic hedgehog signalling in PEComa pathogenesis. The presence of the same somatic mutation in the bilateral tumours might indicate the possibility of a postzygotic somatic mutation that along with the germline mutation of the same gene could represent an intriguing genetic phenomenon (type 2 segmental mosaicism).

Transurethral en bloc resection of a bladder perivascular epithelioid cell tumor (PEComa): a case report.

BACKGROUND: Perivascular epithelioid cell tumor (PEComa) is a mesenchymal tumor with distinct histologic and immunologic features. PEComas that originate in the bladder are extremely rare clinically, with only 35 cases reported in the English literature thus far. Here, we report a case of bladder PEComa resection by transurethral en bloc resection of bladder tumor (ERBT). CASE PRESENTATION: A 66-year-old female with a history of poorly controlled type 2 diabetes with associated complications of frequent urinary tract infections presented to our hospital for a routine physical examination. Outpatient ultrasound examination revealed a strong echogenic mass of approximately 1.5 × 1.3 × 1.3 cm in size on the posterior wall of the bladder. The enhanced computed tomography and enhanced magnetic resonance imaging after admission both suggested a well-defined isolated nodular mass on the posterior wall of the bladder with significant enhancement on the enhanced scan. The tumor was successfully and completely resected by ERBT. Postoperative pathological examination and immunohistochemical results confirmed the mass was a bladder PEComa. No tumor recurrence was observed in the six-month postoperative follow-up. CONCLUSION: Bladder PEComa is an extremely rare mesenchymal tumor of the urinary system. When imaging and cystoscopy reveal a nodular mass with an abundant blood supply in the bladder, PEComa should be included in the differential diagnosis of bladder tumors. Surgical resection is currently the primary option for the treatment of bladder PEComa. For a solitary, pedunculated, narrow-based, small-sized bladder PEComa, resection of the tumor by ERBT was a safe and feasible approach in our patient and may be considered for similar cases in the future.

Risk stratification and outcomes in 210 gynecologic perivascular epithelioid cell tumors (PEComas) cases.

OBJECTIVE: To better understand the risk stratification and outcomes of gynecologic PEComas. METHODS: Clinicopathological features and outcomes of gynecologic PEComas cases reported in both English and Chinese literature before September, 2020 were evaluated. The efficacy of three proposed criteria were compared to verify their practicability in gynecologic PEComas. The Chi-square test and Cox proportional hazard model were performed for statistical analysis. RESULTS: A total of 210 cases were retrieved: 95 from English literature and 115 from Chinese literature. The Flope criterion achieved an accuracy of 47% for detecting malignancy of gynecologic PEComas, 64.2% for the Schoolmeester criterion, and 63.8% for the WHO criterion. Both Chi-square test and uni-variate analysis showed that tumor size ≥ 5 cm, infiltrative growth pattern, mitotic rate ≥ 1/50 high per filed (HPF), high nuclear grade and cellularity, necrosis, and vascular invasion were significantly related to recurrence and/or metastasis (R/M) of gynecologic PEComas. Still only high mitotic rate (≥ 1/50 HPF), high nuclear grade and cellularity, and necrosis significantly influenced the long-term survival. Multi-variate analysis showed high nuclear grade and cellularity was an independent risk factor for R/M of gynecologic PEComas. No model was fitted for the death rate due to a small number of events. When defined malignant PEComas cases as meeting three or more out of six clinicopathologic features, the accuracy of such attempt was 62%, but the false-negative rate dropped by 37-55%. CONCLUSIONS: Gynecologic PEComas with three or more high-risk factors may be considered as malignant. Further efforts should be invested to look for new potential prognostic factors.

Clinicopathological features of primary malignant perivascular epithelioid cell tumors of ureter: Histologic-radiologic correlation.

Perivascular epithelioid cell tumor (PEComa) is a rare mesenchymal tumor that is mainly seen in middle-aged women. PEComa originating in the ureter is extremely rare it is unclear whether they display typical clinical and radiographic features seen elsewhere. Herein, we report findings from 2 cases of primary PEComa of the ureter that we classified as malignant. Case 1: A 45-year-old woman was admitted to the hospital with intermittent distension in her waist. After appropriate imaging, the right ureter and right kidney were excised under general anesthesia. The tumor measured 1.4 cm. Microscopically, the tumor displayed infiltrative growth, >2 mitoses per 10 high power fields (HPF), necrosis, and lympho-vascular invasion. Case 2: A 30-year-old woman was admitted to the hospital due to hematuria 20 days duration. The left ureter and left kidney were ultimately excised under general anesthesia. The tumor measured 2 cm. Microscopically, the tumor showed infiltrative growth and >2 mitoses/10 HPF. Our cases were diagnosed as malignant PEComa. No disease recurrence was observed in either of the two patients during the postoperative follow-up period. Malignant primary ureteral PEComa is very rare. The clinical manifestations are not specific, and it is usually misdiagnosed as a malignant neoplasm on imaging. Therefore, its diagnosis requires pathological examination and immunohistochemical analysis of the sampled or resected tumor. Treatment requires a complete surgical resection and regular clinical follow-up.

Conjunctival Perivascular Epithelioid Cell Neoplasm With RBM10-TFE3 Fusion Presenting as Recurrent Subconjunctival Hemorrhage.

Subconjunctival hemorrhages commonly present to eye care professionals and are frequently regarded as benign self-limited conditions. In selected cases, subconjunctival hemorrhages can be a harbinger of more severe disease. Perivascular epithelioid cell tumors, or PEComas, are rare mesenchymal neoplasms believed to originate from perivascular myoid cells and are rarely present in ocular structures. We present a rare case of a conjunctival perivascular epithelioid cell tumor that initially presented with recurrent subconjunctival hemorrhage. To our knowledge, this is the first description of a PEComa with a RBM10-TFE3 gene fusion, only previously seen with renal cell carcinoma. Physicians should be aware of this rare condition, its location in the fornix and its presentation as a recurrent subconjunctival hemorrhage.

Vaginal metastasis of renal clear cell carcinoma: a case report emphasizing the role of immunohistochemistry in differential diagnosis in the absence of a clinical history.

We present the case of a 71-year-old patient, with vaginal bleeding, dyspnea, headache, loss of appetite and weakness. Clinical examination revealed a pediculated vaginal mass of 25 mm diameter, of dark-red color and soft spongy consistency, with an ulcerated surface and originating from the anterior wall, which was surgically removed. The morphology was dominanted by large, round to polygonal tumor cells, arranged in a predominantly tubulo-cystic architecture, surrounding numerous blood vessels that dominated the appearance, suggesting a perivascular epithelioid cell tumor (PEComa) or hemangioblastoma but the presence of pleomorphic nuclei, numerous mitoses together with immunohistochemistry helped for a correct diagnosis of vaginal .

Perivascular epithelioid cell tumor (PEComa) of the liver. An extremely rare diagnosis.

Hepatic PEComa are tumors that show perivascular epithelioid cell differentiation. Scarcely published, its management is based on small case series and currently its treatment of choice is surgical resection. We present a clinical case of a 74-year-old woman who underwent surgery at our hospital for a benign hepatic PEComa.